Final: Problems with fading alphatexture in .flt

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Jonas Andersson (jonasa++at++cs.umu.se)
Wed, 2 Dec 1998 15:14:57 +0100 (MET)

Problem finally solved by setting the geostate transparency mode to
PFTR_HIGH_QUALITY or PFTR_BLEND_ALPHA.

Thanks a lot Steve, Brett, Rob and Svend for your help. I really
appreciate it!

-- Jonas

On Wed, 2 Dec 1998, Steve Baker wrote:

> On Wed, 2 Dec 1998, Jonas Andersson wrote:
>
> > I have tried doing what you suggested without any change. Also I
> > compared the pfTexture format and filters between the Onyx and Octane,
> > they are exactly the same.
> >
> > There seem to be some default behaviour on the Octane that makes the
> > texture look perfect. This behaviour is not the default on the Onyx (It
> > would be strange if the Octane could produce better results than the Onyx,
> > wouldn´t it :)
> >
> > So my problem remains:
> > What else except the filters and formats could make the difference?
>
> Multisample versus blended alpha.
>
> The Octane probably isn't doing multisampling - so it uses blended alpha
> which produces a higher quality translucency - but which doesn't Z-buffer
> as you would probably like.
>
> The Onyx is probably multisampling (antialiasing) and the Performer default
> is then to use multisampling for alpha too. This severely reduces the number
> of transparency steps between opaque and transparent (which explains the
> difference in your two images) - but it will Z-buffer perfectly (which is
> more important to many people than the quality).
>
> You can force the ONYX to use blended alpha by setting the appropriate
> state in the pfGeoState - but you can't force the Octane to use multisample
> unless it has a multisample-capable graphics adaptor and enough memory
> to turn that stuff on. I don't use Octanes - so I don't know for sure.
>
> Steve Baker (817)619-2657 (Vox/Vox-Mail)
> Raytheon Systems Inc. (817)619-2466 (Fax)
> Work: sjbaker++at++hti.com http://www.hti.com
> Home: sjbaker1++at++airmail.net http://web2.airmail.net/sjbaker1
>
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-- Jonas
________________________________________________________________________________
Jonas Andersson jonasa++at++acc.umu.se, http://www.cs.umu.se/~jonasa

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